I went through all the hustle and bustle of applying for CPP and AISH (Assured Income for the Severely Handicapped). You're right, it does take months. For me, it took a year. My first request for benefits resulted in a denial. So I had to appeal the decision. It took forever. Even with all the doctor letters (and I had a pile), I was denide.
I'm surprised that your new doctor isn't being proactive in getting these letters written. Have you had all your files transferred over from your old doctor? Gosh, this new one should know how critical it is to get this going fast.
Keep "harrassing" your doctor until he gets it. I wish I had more suggestions for you Bryan. My issue was with the government denying me. My doctor was great. I'm sorry you're facing this. It just adds more stress to your life and that's not healthy at all.
Keep us posted okay?